This invention relates to walls in which a frame structure has an infill, over at least a part of the area of the wall, of multiple layer panels providing an air gap between inner and outer leaves, e.g. being double- or triple-glazed.
While it is normal practice to form such multiple layer panels so that the air spaces within them are completely sealed, imperfections of construction or simply the effects of time often result in leakage and even small flows can give rise to fogging of glass areas. Also, if condensed vapour is allowed to stand in contact with many of the materials used for the wall infill, including the rubbery materials that are commonly relied on to provide sealing, it can cause deterioration.